Cases of walking pneumonia are on the rise in young children, according to the Centers for Disease Control. The disease, which is caused by the bacteria Mycoplasma pneumoniae, is less serious than standard pneumonia, although it can be harmful in some cases. 

According to the Centers for Disease Control: 

“The M. pneumoniae discharge diagnosis data from March 31 through October 5, 2024, show an increase among all age groups across the United States, peaking in August, and remaining high. The increase, however, was highest among children. The percentage grew from 1.0% to 7.2% among children ages 2–4 years and from 3.6% to 7.4% among children ages 5–17 years in that time frame. The increase in children ages 2–4 years is notable because M. pneumoniae historically hasn't been recognized as a leading cause of pneumonia in this age group.”